|By Shadia Nasralla

VIENNA (Reuters) - Austria is pursuing plans to give police authority to monitor messaging services such as WhatsApp <FB.O> and Skype in an attempt to "close the gap" on criminals who increasingly avoid communicating via telephone.

The government asked political, technology, civil rights and legal experts to review draft legislation that would give it authority to monitor real-time conversations using new messaging services and applications, Justice Ministry officials told Reuters on Monday.

Such surveillance would be permitted only with a court order in investigations into terrorist activities or other crimes punishable by at least five years in prison, one of the officials said.

Other European countries with similar laws include France, Italy, Poland and Spain, the ministry said.

It was not immediately clear how Austria would conduct such surveillance, though one approach would be to install software on computers and mobile devices of suspects using messaging tools with end-to-end encryption that prevents the government from accessing it using traditional, remote eavesdropping techniques.

Such tools are sold by a handful of firms that specialize in selling off-the-shelf surveillance tools, or spyware, to governments.

"Law enforcement and intelligence agencies are gravitating toward this type of spyware to overcome the challenge of end-to-end encryption," said Ronald Deibert, director of the Citizen Lab at the Munk School of Global Affairs in Toronto.

Deibert, whose institute investigates abuse of such tools, said it is important for governments to make sure they have proper oversight and public accountability when giving authorities the right to use new surveillance technologies.

Austrian courts have already sentenced several people to prison for links to terrorist organizations after verdicts that were supported by data acquired from seized devices. The proposed legislation provides authorization for obtaining data from devices that have not been seized.

The government plans to submit the bill to parliament after an Aug. 21 deadline for submission of opinions.

In Germany, police and intelligence services have authority to install malware on suspect phones, but this is highly controversial and it is unclear how widely it is used.

In the Netherlands, the Senate is scheduled to vote on Tuesday on digital security legislation with provisions to let intelligence services target criminal suspects with malware.

Britain's Intelligence Act, which is still being implemented, explicitly gives power to police and intelligence services for the mass interception of communications.

(Additional reporting by Eric Auchard and Peter Maushagen in Frankfurt, and Dustin Volz in Washington; Editing by Jim Finkle and Matthew Lewis)